Compatibilized polymer blends formed using a multifunctional agent

ABSTRACT

A compatibilized blend of general purpose rubbers (GPR) and benzyl halide polymers are produced through solventless reactions utilizing a multifunctional agent containing a diene reactive group and a benzylic halo reactive group.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention is directed to compatibilized polymer blends formedusing a multifunctional agent in a polymer blend, preferably consistingof general purpose rubbers and benzyl halide containing polymers.

[0003] 2. Related Art

[0004] Relatively saturated elastomeric polymers, such as butyl rubber,which is a copolymer of isobutylene with a small percentage of isopreneunits are known. These polymers demonstrate low air permeability,relatively low glass transition temperatures, broad damping peaks,excellent environmental aging resistance, and other such propertieswhich render these polymers of commercial significance in blends withpolymers or in tire production. Butyl rubber generally is incompatiblewith most other polymers.

[0005] It has been known for some time that blends of incompatiblepolymers can be improved in some cases by adding a suitablecompatibilizer so as to alter the morphology of these blends. Moreparticularly, to be successful it has been necessary to reduce thedomain sizes for both of the polymers in the blend.

[0006] It is known in some instances to use block copolymers ascompatibilizers. For example, several studies have shown attempts tocompatibilize rubber-rubber blends of polyisoprene and polybutadiene byusing diblock materials composed of these two materials. See R. Cohen etal. Macromolecules 15, 370, 1982; Macromolecules 12, 131, 1979; J.Polym. Sci., Polym. Phys. 18, 2148, 1980; J. Macromol. Sci.-Phys. B17(4), 625, 1980. Most of these block copolymers have been previouslyproduced by sequential anionic polymerization processes, which are thuslimited to a relatively small number of monomers. It is also known tocompatibilize other blends, such as rubber-plastic blends ofethylene-propylene rubber with polypropylene, by using graft copolymersof these two materials. See A. Y. Coran et al., U.S. Pat. No. 4,299,931,as well as co-pending commonly assigned applications Ser. No. 07/264,484now U.S. Pat. No. 4,999,403 and Ser No. 07/264,485, filed on Oct. 28,1988.

[0007] Others have proposed different solutions for preparingcompatibilized blends comprising isoolefin polymers. For example, Wang,in WO 95/09197 describes intervulcanizable blends comprising a mixtureof a diolefin polymer or copolymer and a saturated or highly saturatedelastomeric copolymer having a number average molecular weight of atleast 10,000 and containing from about 0.01 up to about 10 mole % of “Y”functional groups randomly distributed along and pendant to theelastomeric polymer chain, said Y functional groups containing anolefinic or vinyl double bond positioned alpha, beta to a substituentgroup which activates said double bond towards free radical additionreactions. The preferred activating substituent groups arecarboxyl-containing groups, phosphoryl-containing groups,sulfonyl-containing groups, nitrile-containing groups, aromaticring-containing groups or a combination of such groups.

[0008] It would be desirable to obtain a process not employing asolvent. The present invention provides compatibilized blends formed bya solventless reaction between two generally incompatible polymers witha multifunctional compound/agent.

SUMMARY OF THE INVENTION

[0009] The invention is directed to a solventless process for formingcompatibilized blends of general purpose rubbers and benzyl halidepolymers comprising mixing at least one general purpose rubber and abenzyl halide containing polymer in the presence of a multifunctionalagent, said agent comprising a compound represented by the generalformula (X)_(n)—(R)_(m)—(Y)_(p), wherein m is equal to or greater thanzero, and desirably range from about 1 to about 10, n and p are greaterthan zero and desirably range from about 1 to about 100. X is dienereactive group. Preferably the diene reactive group is selected from thegroup consisting of (1) enophiles, (2) free radicals and radical traps,(3) free radical traps, and (4) nucleophiles. R is selected from thegroup consisting of alkyls, aryls, alkyl substituted aryls preferablyhaving from about 1 to about 100 carbon atoms and polymers. And Y is abenzylic halogen reactive group, like a nucleophile. In addition, thepresent invention is also directed to using compatibilized blends of thepresent invention to compatibilize other polymer blends by mixing thecompatibilized blend with at least one general purpose rubber and atleast one polymer to form a new compatibilized blend.

[0010] The invention is further directed to a compatibilized blend ofgeneral purpose rubbers and benzyl halide containing polymers comprisingmixing general purpose rubbers, benzyl halide containing polymers and amultifunctional agent comprising a compound having the formula(X)_(n)—(R)_(m)—(Y)_(p), wherein m is equal to or greater than zero, nand p are greater than zero, X is a diene reactive group, R is selectedfrom the group consisting of alkyls, aryls, alkyl substituted arylshaving from about 1 to about 100 desirably 1-20 carbon atoms andpolymers, and Y is a benzylic halide reactive group. In addition, thepresent invention is directed to the cured compatibilized blendsdescribed above.

DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention is directed to compatibilized blends ofgeneral purpose rubbers (“GPR”) and benzyl halide containing polymers.The present invention is also directed to a process for the productionof compatibilized blends of GPR and benzyl halide containing polymers.Moreover, the present invention is directed to compatibilized blends ofGPR and poly(isobutylene-co-methylstyrene) containing 4-halomethyleneunits (hereinafter BIPMS) disclosed in U.S. Pat. No. 5,162,445, hereinincorporated by reference. The present invention is further directed toa solventless process for the production of compatibilized blends of GPRand BIPMS. In addition, the present invention is directed to utilizingcompatibilized blends of the present invention to compatibilize otherpolymer blends.

[0012] In a particularly preferred embodiment, the compatibilized blendsof the present invention are comprised of a blend of general purposerubbers and BIPMS. The benzyl halide copolymers are desirablyelastomeric copolymers of isobutylene, a para-methyl styrene containingfrom about 0.5 to about 20 mole percent para-methyl styrene wherein upto about 60 mole % of the methyl substituent groups present on thearomatic ring contain a bromine or chlorine atom. These copolymers andtheir method of preparation are disclosed in U.S. Pat. No. 5,162,445,hereby incorporated by reference. The blends of the present inventionmay include but are not limited to the following general purposerubbers: natural rubber (NR), polyisoprene (IR), polybutadiene (BR),poly(styrene-co-butadiene) (SBR), and poly(acrylonitrile-co-butadiene)(NBR).

[0013] Generally, the blends of the present invention may comprise fromabout 5 to about 95 percent by weight GPR and from about 5 to about 95percent by weight benzyl halide containing polymer. Preferably theblends comprise from about 15 to about 85 percent by weight GPR and fromabout 15 to about 85 percent by weight benzyl halide containing polymer.Most preferably, the blends of the present invention are comprised ofabout 30 to about 70 percent by weight GPR and from about 30 to about 70percent by weight benzyl halide containing polymer. The multifunctionalagent employed in the practice of the present invention generallycomprises from about 0.01 to about 10 percent by weight, preferably 0.01to about 3 percent, of the total blend weight.

[0014] The process of the present invention may be carried out in asingle step or in two steps. For example, the multifunctional agent maybe mixed with the GPR or the benzyl halide polymer first and then addedto the other component with mixing and heating. Alternatively, theprocess of the present invention may be carried out in a single pass orstep wherein the multifunctional agent, GPR, and benzyl halide polymerare mixed and heated together simultaneously.

[0015] Utilizing either process described above, the reaction isconducted under solventless conditions using internal mixers, extruders,and rubber milling equipment. Typical mixers include Brabender™ andBanbury™ mixers. As stated above, the rubber compositions are placed inthe mixers along with the multifunctional agent and reacted under shearand heat to yield the compatibilized blends of the present invention.

[0016] The multifunctional agent of the present invention is amultifunctional compound containing both a diene reactive group and abenzyl halide reactive group. The multifunctional agent of the presentinvention has the following formula: (X)_(n)—(R)_(m)—(Y)_(p), wherein mis equal to or greater than zero, and n and p are equal to or greaterthan one. X is a diene reactive group and may be selected from the groupconsisting of (1) enophiles, (2) free radicals and free radical traps,(3) free radical traps and (4) nucleophiles. The enophiles which areuseful in the practice of the present invention include, but are notlimited to, maleic anhydride and its activated derivatives, includingbut not limited to carboxy maleic, sulfo maleic, methyl maleic, andphenyl maleic, etc., as well as the analogous nitrogen species,triazolinediones. The free radical sources useful in the practice of thepresent invention include, but are not limited to, peroxides, azocompounds, and polymer bond cleavage, i.e., radicals formed during GPRmastication. Preferred peroxides include dicumyl peroxide, di-t-butylperoxide, benzoyl peroxide, bis p-chlorobenzoyl peroxide, and t-butylcumyl peroxide. Preferred azo compounds include 2,2′-azobis(isobutyronitrile); 1,1′-azo bis(cyclohexanecarlonitrile); 4,4′-azobis(4-cyanovaleric acid); and 2,2′-azo bis(2-amidinopropane).

[0017] The radicals can either add to the olefin or extract a protonleading to polymeric radicals. These radicals can be trapped usingsuitable radical sinks or traps, e.g., sulphides, sulphenylchlorides,and thioacids. Alternately, the radicals can be trapped utilizingfree-radical polymerizable monomers, e.g., acrylic, and methacrylicacid.

[0018] Y is the benzylic halide reactive group and is a nucleophile.Preferably, the nucleophilic groups which are useful in the practice ofthe present invention include, but are not limited to carboxylates,amines, phosphines, alkoxides, phenoxides, and thiolates.

[0019] R may be an alkyl, aryl or an alkyl-substituted aryl containingfrom about 1 to about 100 carbon atoms, or a polymer having a Mw up toabout 100,000. Polymers which are suitable as R may be prepared bycontrolled polymerization methods such as “living” anionic, cationic, orfree-radical reactions. These “living polymers” are convenientlyprepared by contacting the monomers or combination of monomers with apolymerization initiator in the presence of an inert organic diluentwhich does not participate in or interfere with the polymerizationreaction. For example, dimethylaminopropyllithium may be used toinitiate the “living” polymerization of dienes like butadiene andisoprene. This “living” chain is then terminated with propylene sulfide.The polymer thus has an end which can react with benzylhalide and asecond end which is diene reactive. Alternatively, polymers suitable asR may be obtained by ring-opening polymerization of cyclic monomersusing a suitable functionalized initiator. The molecular weight of the Rpolymer may vary depending upon the application; however, typicallypolymers desirably having a molecular weight ranging from about 500 toabout 100,000 are useful in the practice of the present invention.

[0020] The compatibilized blends of the present invention may be curedgenerally using curing systems known in the rubber industry. Forexample, curing systems useful in curing the blends of the presentinvention include but are not limited to systems comprising sulfurcompounds, zinc compounds, metal compounds, radical initiators, etc.Specific compounds useful as curatives in the present invention include,but are not limited to, zinc oxide, stearic acid, tetramethylthiuramdisulfide (TMTD), 4,4′-dithiodimorpholine (DTDM), tetrabutylthiunramdisulfide (TBTD), benzothiazyl disulfide (MBTS),hexamethylene-1,6,-bisthiosulfate disodium salt dihydrate (ERP 390),2-(morpholinothio) benzothiazole (MBS or MOR), blends comprising 90% byweight MOR and 10% by weight MBTS (MOR90), N-oxydiethylenethiocarbamyl-N-oxydiethylene sulfenamide (OTOS) zinc 2-ethyl hexanoate(2EH); and MC sulfur.

[0021] The present invention, while not meant to be limited by, may bebetter understood by reference to the following examples.

[0022] In the following examples, the benzyl halide containing polymer(BIPMS) was brominated poly(isobutylene-co-4-methyl styrene containing7.5 wt percent, 4-methyl styrene, and 2 wt percent benzyl bromide, andhaving a Mooney viscosity ML(1+8) 125° C. of 45±5.

EXAMPLE I

[0023] Compatibilization of Natural Rubber with BIPMS

[0024] Radicals Generated During Mastication and TetramethylammoniumMercaptoacetate Salt as Radical Trap

[0025] a. The tetramethylammonium mercaptoacetate salt (hereinafter“salt”) was prepared through neutralization of commercially availablematerials. 0.921 g of 0.01 M Mercaptoacetic acid (obtained from Aldrich)was neutralized with 3.646 g of 0.01 M tetramethylammonium hydroxide(obtained as a 25 weight percent methanol solution from Aldrich). Thewater and methanol were removed under vacuum to yield a white salt.

[0026] b. Two Pass Compatibilized Blend: 40 g of NR was placed in aBrabender™ cavity along with 0.25 g of the salt, prepared previously.The rubber salt mixture was masticated at 50 rpm and 60° C. for 15minutes. The contents of the Brabender™ were removed. A fraction of thereacted natural rubber was placed in the Brabender™ along with 35 g ofBIPMS. The mixture was mixed at 20° C. and 10 rpm for 5 minutes. TheBrabender™ was then heated to 50° C. at which time the speed wasincreased to 100 rpm. Under these conditions, the temperature increasedto 115° C. The mixture was kept at 100 rpm and 115° C. for 15 minutesand then removed. The compatibilized blend was then compared to anoncompatibilized blend using electron microscopy. The results arereported in Table 1 below.

EXAMPLE 2

[0027] Graft Reaction of Natural Rubber with BIPMS

[0028] Using Radicals Generated from Peroxide (Dicumyl Peroxide) andTetrabutylammonium Methacrylate as Radical Trap in a Single Pass Mix

[0029] a. The salt was prepared by neutralizing commercially availablematerials.

[0030] 0.874 g of methacrylic acid was neutralized with 10 ml of a 1molar solution of tetrabutylammonium hydroxide in methanol. The methanolwas removed under nitrogen to yield a white salt.

[0031] b. One pass compatibilized blend: 33.2 g BIPMS and 14.23 g ofnatural rubber were placed in a Brabender™ mixer. The rubber was mixed 5minutes at 85-90° C. and 60 rpm. The temperature was raised to 150° C.and 0.051 g of dicumyl peroxide and 0.471 g of the tetrabutylammoniummethacrylate was added. The mix was reacted for an additional fiveminutes. The compatibilized blend was then compared to anoncompatibilized blend using electron microscopy. The results arereported in Table 1 below.

EXAMPLE 3

[0032] Graft Reaction of Polybutadiene with BIPMS

[0033] Using Radicals Generated from Peroxide (Dicumyl Peroxide) andTetrabutylammonium 6,8 Dithiooctanoate as Radical Trap in a Two Pass Mix

[0034] a. The salt was prepared by neutralizing commercially availablematerials. 0.2064 g of 6,8-dithiooctanoic acid was neutralized with 10.1ml of a 1 molar solution of tetrabutylammonium hydroxide in methanol.The methanol and water were removed under nitrogen to yield a yellowproduct.

[0035] b. Two pass compatibilized blend: 47.12 g of polybutadiene wasplaced in a Brabender™ mixer and mixed 5 minutes at 50° C. and 40 rpm.The temperature was raised to 150-160° C. and 0.051 g of dicumylperoxide and 0.471 g of the tetrabutylammonium methacrylate was added.The mix was reacted for an additional five minutes. The contents of theBrabender™ mixer were removed. A fraction of the reacted polybutadiene(14.76 g) was placed in the Brabender™ mixer along with 33.5 g of BIPMS.The mixture was mixed at 20° C. and 10 rpm for 5 minutes. The Brabender™mixer was then heated to 110° C. at which temperature the speed wasincreased to 80 rpm. Under these conditions, the temperature increasedto 115° C. These conditions were maintained for 5 minutes and then thecompatibilized blend was removed. The compatibilized blend was thencompared to a noncompatibilized blend using electron microscopy. Theresults are reported in Table 1 below.

EXAMPLE 4

[0036] Graft Reaction of Nitrile Rubber (Paracril B) with BIPMS Using

[0037] Radicals Generated from Peroxide (Dicumyl Peroxide) andTetrabutylammonium 6,8-dithiooctanoate as Radical Trap in a Two Pass Mix

[0038] a. The salt was prepared by neutralizing commercially availablematerials: 2064 g of 6,8-dithiooctanoic acid was neutralized with 10.1ml of a 1 molar solution of tetrabutylammonium hydroxide in methanol.The methanol and water were removed under nitrogen to yield a yellowproduct.

[0039] b. Two pass compatibilized blend: 47.5 g of nitrile rubber wasplaced in a Brabender™ mixer and mixed 5 minutes at 50° C. and 40 rpm.The temperature was raised to 150-160° C. and 0.051 g of dicumylperoxide and 0.487 g of the tetrabutylammonium methacrylate was added.The mix was reacted for an additional five minutes. The contents of theBrabender™ mixer were removed. A fraction of the reacted nitrile rubber(14.76 g) was placed in the Brabender™ mixer along with 33.5 g of BIPMS.The mixture was mixed at 20° C. and 10 rpm for 5 minutes. The Brabender™mixer was then heated to 155° C. at which temperature the speed wasincreased to 80 rpm. Under these conditions, the temperature increasedto 180° C. These conditions were maintained for 5 minutes and then thecompatibilized blend was removed. The compatibilized blend was thencompared to a noncompatibilized blend using electron microscopy. Theresults are reported in Table 1 below.

EXAMPLE 5

[0040] Graft Reaction of Polybutadiene with BIPMS Using

[0041] Radicals Generated from Peroxide (Dicumyl Peroxide) andTetrabutylammonium Mercaptoacetate as Radical Trap in a Two Pass Mix

[0042] a. The salt was prepared by neutralizing commercially availablematerials. 0.9212 g of mercaptoacetic acid was neutralized with 10.1 mlof a 1 molar solution of tetrabutylammonium hydroxide in methanol. Themethanol and water were removed under nitrogen to yield a white product.

[0043] b. Two pass compatibilized blend: 47.12 g of polybutadiene wasplaced in a Brabender™ mixer and mixed 5 minutes at 50° C. and 40 rpm.The temperature was raised to 150-160° C. and 0.051 g of dicumylperoxide and 0.471 g of the tetrabutylammonium methacrylate was added.The mix was reacted for an additional five minutes. The contents of theBrabender™ mixer were removed. A fraction of the reacted polybutadiene(14.76 g) was placed in the Brabender™ mixer along with 33.5 g of BIPMS.The mixture was mixed at 20° C. and 10 rpm for 5 minutes. The Brabender™mixer was then heated to 110° C. at which temperature the speed wasincreased to 80 rpm. Under these conditions, the temperature increasedto 115° C. These conditions were maintained for 5 minutes and then thecompatibilized blend was removed. The compatibilized blend was thencompared to a noncompatibilized blend using electron microscopy. Theresults are reported in Table 1 below.

EXAMPLE 6

[0044] Graft Reaction of Natural Rubber with BIPMS Using

[0045] Radicals Generated from Peroxide (Dicumyl Peroxide) andTetrabutylammonium Dithiopropionate as Radical Trap in a Single Pass Mix

[0046] a. The salt was prepared by neutralizing commercially availablematerials. 2.108 g of dithiopropionic acid was neutralized with 10 ml ofa 1 molar solution of tetrabutylammonium hydroxide in methanol. Themethanol and water were removed under nitrogen to yield a white salt.

[0047] b. One pass compatibilized blend: 33.22 g BIPMS and 14.21 g ofnatural rubber were placed in a Brabender™ mixer. The rubber was mixed 5minutes at 100° C. and 60 rpm. The temperature was raised to 150° C. and0.05 g of dicumyl peroxide and 0.5 g of the tetrabutylammoniumdithopropionate was added. The mix was reacted for an additional fiveminutes. The compatibilized blend was then compared to anoncompatibilized blend using electron microscopy. The results arereported in Table 1 below.

EXAMPLE 7

[0048] Graft Reaction of Styrene-Butadiene Rubber with BIPMS UsingRadicals

[0049] Generated from Azo-decomposition of Tetrabutylammonium4,4azobiscyanovalerate in a Single Pass Mix

[0050] a. The salt was prepared by neutralizing commercially availablematerials. 4.17 g of 4,4azobiscyanovalerate was neutralized with 40 mlof a 1 molar solution of tetrabutylammonium hydroxide in methanol. Themethanol and water were removed under nitrogen to yield a white product.

[0051] b. Single pass compatibilized blend: 82.02 g of styrene-butadienerubber (SBR 1502) and 191.38 g of BIPMS were placed in a B-Banbury™mixer along with 1.37 g of tetrabutylammonium 4,4azobiscyanovalerate.The mix was dropped at 180° F. after 3 minutes of mixing. The rubber mixinternal temperature was measured with a pyrometer after dropping. Therubber was typically 50° F. higher in temperature than the Banbury™ droptemperature. The compatibilized blend was then compared to anoncompatibilized blend using electron microscopy. The results arereported in Table 1 below.

[0052] All blends were characterized using low voltage scanning electronmicroscopy on osmium stained images. The phase size information wasobtained by sampling the image using lines drawn at random on theimages. The data was collected at two magnifications (9,000 and 20,000).The average dispersed phase for the compatibilized blend and acomparative control are presented in Table 1 below. The smaller thedispersed phase size the more compatibilized the blend. TABLE 1Dispersed Phase Size Results for Examples 1-7. CompatibilizedComparative Blend Dispersed Phase Dispersed Phase Example # Size(micrometers) Size (micrometers) 1 0.1 .5 2 0.1 1 3 0.2 2 4 0.7 30 5 0.72 6 0.2 2 7 0.7 3

[0053] In addition to controlling the phase size one can practice thereaction in a manner which produces polymer phase inversion. Thefollowing examples are illustrative of this benefit.

EXAMPLE 8

[0054] Graft Reaction of Natural Rubber with BIPMS Using Radicals

[0055] Generated from Peroxide (Dicumyl Peroxide) and TetrabutylammoniumThiosalicylate as Radical Trap in a Single Pass Mix

[0056] a. The salt was prepared by neutralizing commercially availablematerials. 1.546 g of thiosalicylic acid was neutralized with 10 ml of a1 molar solution of tetrabutylammonium hydroxide in methanol. Themethanol and water were removed under nitrogen to yield a white salt.

[0057] b. One pass compatibilized blend: 33.27 g of BIPMS and 14.24 g ofnatural rubber were placed in a Brabender™ mixer. The rubber was mixed 5minutes at 100° C. and 60 rpm. The temperature was raised to 150° C. and0.05 g of dicumyl peroxide and 0.5 g of the tetrabutylammoniumthiosalicylate was added. The mix was reacted for an additional fiveminutes. The resultant blend comprised a continuous natural rubber phasewith 1 micrometer dispersed phase.

EXAMPLE 9

[0058] Graft Reaction of Natural Rubber with BIPMS Using Radicals

[0059] Generated from Peroxide (Dicumyl Peroxide) and TetrabutylammoniumThiosalicylate as Radical Trap in a Two Pass Mix

[0060] a. The salt was prepared by neutralizing commercially availablematerials. 1.546 g of thosalicylic acid was neutralized with 10 ml of a1 molar solution of tetrabutylammonium hydroxide in methanol. Themethanol and water were removed under nitrogen to yield a white salt.

[0061] b. Two pass compatibilized blend: 47.48 g of natural rubber wasplaced in a Brabender™ mixer and mixed 5 minutes at 50° C. and 40 rpm.The temperature was raised to 150-160° C. and 0.051 g of dicumylperoxide and 0.49 g of the tetrabutylammonium thiosalicylate was added.The mix was reacted for an additional five minutes. The contents of theBrabender™ mixer were removed. A fraction of the reacted natural rubber(14.35 g) was placed in a Brabender™ mixer along with 33.59 g of BIPMS.The mixture was mixed at 20° C. and 10 rpm for 5 minutes. The Brabender™mixer was then heated to 110° C. at which temperature the speed wasincreased to 80 rpm. Under these conditions, the temperature increasedto 115° C. These conditions were maintained for 5 minutes and then thecompatibilized blend was removed. The resultant blend comprised acontinuous BIPMS phase with a 0.5 micrometer dispersed natural rubberphase.

I claim:
 1. A solventless process for forming compatibilized blends ofat least one general purpose rubber and at least one benzyl halidecontaining polymer comprising: mixing the general purpose rubber andbenzyl halide containing polymer in the presence of a multifunctionalagent to form a compatibilized blend, said agent comprising a compoundrepresented by the general formula (X))_(n)—(R)_(m)—(Y)_(p), wherein mis equal to or greater than zero, n and p are greater than zero, X isselected from the group consisting of enophiles, free radicals andradical traps, radical traps, and nucleophiles, R is selected from thegroup consisting of alkyls, aryls, alkyl substituted aryls and polymers,and Y is a nucleophile.
 2. The process of claim 1 wherein Y is selectedfrom the group consisting of carboxylates, amines, phosphines,alkoxides, phenoxides, and thiolates.
 3. The process of claim 1 whereinX is selected from the group consisting of triazolinediones, maleicanhydride, methyl maleic anhydride, phenyl maleic anhydride, sulfomaleic anhydride, carboxy maleic anhydride, and derivatives thereof. 4.The process of claim 1 wherein X comprises a free radical trap selectedfrom the group consisting of sulphides, sulphenylchlorides, thioacids,acrylic acid, and methacrylic acid.
 5. The process of claim 1 wherein Rcomprises from about 1 to about 100 carbon atoms.
 6. The process ofclaim 1 wherein the benzyl halide polymer comprisespoly(isobutylene-co-methylstyrene) containing 4-halomethylene units. 7.The process of claim 1 wherein the general purpose rubbers are mixedwith the multifunctional agent before mixing with the benzyl halidepolymer.
 8. The compatibilized blend produced according to claim
 1. 9.The process of claim 1 further comprising the additional step of mixingthe compatibilized blend with at least one general purpose rubber and atleast one polymer to form a new compatibilized blend.
 10. A process forcompatibilizing a blend of general purpose rubber andpoly(isobutylene-co-methylstyrene) containing 4-halomethylstyrene units(BIPMS) comprising mixing: at least one general purpose rubber, at leastone BIPMS polymer, and a multifunctional agent comprising a compoundrepresented by the formula (X)_(n)—(R)_(m)—(Y)_(p), wherein m is equalto or greater than zero, n and p are greater than zero, X comprises adiene reactive group, R is selected from the group consisting of alkyls,aryls, alkyl substituted aryls and polymers, and Y comprises a benzylichalo reactive group.
 11. The process of claim 10 wherein X of themultifunctional agent is selected from the group consisting ofenophiles, free radicals and radical traps, radical traps, andnucleophiles, and Y comprises nucleophiles.
 12. The process of claim 10wherein R of the multifunctional agent comprises 1 to 100 carbon atoms.13. The process of claim 10 wherein X of the multifunctional agent isselected from the group consisting of maleic anhydride, methyl maleicanhydride, phenyl maleic anhydride, sulfo maleic anhydride, carboxymaleic anhydride, triazolinediones, and derivatives thereof.
 14. Theprocess of claim 10 wherein Y of the multifunctional agent is selectedfrom the group consisting of carboxylates, amines, phosphines,alkoxides, phenoxides, and thiolates.
 15. The compatibilized blendproduced according to claim
 10. 16. The process of claim 10 furthercomprising the step of mixing the blend with at least one generalpurpose rubber and at least one benzyl halide polymer to form a newcompatibilized blend.
 17. A compatibilized blend of at least one generalpurpose rubber and at least one benzyl halide polymer comprising areaction mixture of: a general purpose rubber, a benzyl halide polymer,and a multifunctional agent comprising a compound represented by thegeneral formula (X)_(n)—(R)_(m)—(Y)_(p), wherein m is equal to orgreater than zero, n and p are greater than zero, X comprises a dienereactive group, R is selected from the group consisting of alkyls,aryls, alkyl substituted aryls, and polymers, and Y comprises a benzylichalide reactive group.
 18. The blend of claim 17 wherein X is selectedfrom the group consisting of enophiles, free radicals and radical traps,radical traps, and nucleophiles.
 19. The blend of claim 17 wherein Y isselected from the group consisting of carboxylates, amines, phosphines,alkoxides, phenoxides, and thiolates.
 20. The blend of claim 17 whereinX is selected from the group consisting of sulphides,sulphenylchlorides, thioacids, acrylic acid, and methacrylic acid. 21.The blend of claim 17 wherein X is selected from the group consisting oftriazolinediones, maleic anhydride, methyl maleic anhydride, phenylmaleic anhydride, sulfo maleic anhydride, carboxy maleic anhydride, andderivatives thereof.
 22. The blend of claim 17 wherein Y comprises anucleophile.
 23. The compatibilized blend of claim 17 wherein said blendis cured.